Re: [PATCH 11/11] fs/ntfs3: Taking DOS names into account during link counting

[Konstantin Komarov]

On 18.04.2024 09:31, Johan Hovold wrote:
> On Wed, Apr 17, 2024 at 04:10:59PM +0300, Konstantin Komarov wrote:
> > When counting and checking hard links in an ntfs file record,
> >
> >     struct MFT_REC {
> >       struct NTFS_RECORD_HEADER rhdr; // 'FILE'
> >       __le16 seq;        // 0x10: Sequence number for this record.
> >   >>  __le16 hard_links;    // 0x12: The number of hard links to record.
> >       __le16 attr_off;    // 0x14: Offset to attributes.
> >     ...
> >
> > the ntfs3 driver ignored short names (DOS names), causing the link count
> > to be reduced by 1 and messages to be output to dmesg.
> I also reported seeing link counts being reduced by 2:
>
> [   78.307412] ntfs3: nvme0n1p3: ino=34e6, Correct links count -> 1 (3).
> [   78.307843] ntfs3: nvme0n1p3: ino=5bb23, Correct links count -> 1 (2).
> [   78.308509] ntfs3: nvme0n1p3: ino=5c722, Correct links count -> 1 (2).
> [   78.310018] ntfs3: nvme0n1p3: ino=5d761, Correct links count -> 1 (2).
> [   78.310717] ntfs3: nvme0n1p3: ino=33d18, Correct links count -> 1 (3).
> [   78.311179] ntfs3: nvme0n1p3: ino=5d75b, Correct links count -> 1 (3).
> [   78.311605] ntfs3: nvme0n1p3: ino=5c708, Correct links count -> 1 (3).
>
>   - https://lore.kernel.org/all/Zhz_axTjkJ6Aqeys@xxxxxxxxxxxxxxxxxxxx/
>
> Are you sure there are not further issues with this code?
>
> > For Windows, such a situation is a minor error, meaning chkdsk does not
> > report
> > errors on such a volume, and in the case of using the /f switch, it silently
> > corrects them, reporting that no errors were found. This does not affect
> > the consistency of the file system.
> >
> > Nevertheless, the behavior in the ntfs3 driver is incorrect and
> > changes the content of the file system. This patch should fix that.
> This patch is white space damaged and does not apply.
>
> > PS: most likely, there has been a confusion of concepts
> > MFT_REC::hard_links and inode::__i_nlink.
> I'd also expect a Fixes and CC stable tag here.
>
> And as this patch does not seem to depend on the rest of the series it
> should go first (along with any other bug fixes).
>
> > Signed-off-by: Konstantin Komarov <almaz.alexandrovich@xxxxxxxxxxxxxxxxxxxx>
> Johan

Hi Johan,

We are in the process of extending the tests for link counting and 
related scenarios.

If I find bugs, I'll reply ASAP.

Thanks for highlighting the bug.